Sinistral Sentence Examples
Shell bulimoid, dextral or sinistral; radular teeth, expanded at their extremities and multicuspidate.
The same, mutatis mutandis, may occur in sinistral shells.
Lanistes, shell sinistral, spire short or obsolete.
This, however, is not generally retained in one plane, and the spire projects, little by little, on the side which was originally left, but finally becomes right (in dextral forms, with a clockwise direction, if viewed from the side of the spire; but counter-clockwise in sinistral forms).
Its opening, the vent, is situated either on the middle line at the base of the tail, or on the right side, as if to balance the sinistral position of the spiraculum.Advertisement
The essential feature of the asymmetry of Gastropoda is the atrophy or disappearance of the primitively left half of the circumanal complex (the right half in sinistral forms), including the gill, the auricle, the osphradium, the hypobranchial gland and the kidney.
When the shell is sinistral the asymmetry of the organs is usually reversed, and there is a complete situs inversus viscerum, the direction of the spiral of the shell corresponding to the position of the organs of the body.
Triforis, Physa, Clausilia are examples of sinistral Gastropods, but reversal also occurs as an individual variation among forms normally dextral.
In Planorbis, which is sinistral (as are a few other genera or exceptional varieties of various Anisopleurous Gastropods).
Visceral mass and shell sinistral; inferior pallial lobe very prominent, and transformed into a branchia.Advertisement
The shell of Clausilia is sinistral and its aperture is provided with a hinged plate.
It projects horizontally forwards from the head in the form of a cylindrical or slightly tapering, pointed tusk, composed of ivory, with a central cavity reaching almost to the apex, without enamel, and with the surface marked by spiral grooves and ridges, running in a sinistral direction.